Autos are kind of fickle - some blast thru its short veg some are literally “ late bloomers “ and won’t get their final size until it hits preflower stretch . However ANY kind of stress ( wonky feeds , excess flush , overwatering , etc. ) can impact autos upfront.
Autos are kind of easy - they need very little up front - SIMPLE feed requirements ( either from host medium / simple 2 part nute or dry fertilizer top dressed ). Sure some “ breeders “ sling first gen seeds from breeding. But they ONLY require about 90 days of average life.
I grow more autos than i care to mention and if you really pull back on high ppm feeds you will find these are just plug and play plants. Your host Medium ( if soil ) will FEED that plant alone for weeks without much else. Most good ammended soils have enough nutes precharged in it to run on just water. I use standard tap at ph 6.5 and let it do its thing ... if soil looks to start exhausting, i just TOP DRESS MORE SOIL ON TOP and just water in .... stupid simple.
Or you can ANY good dry fertilizer like Megacrop , Dr. Earth ( homegrown/ flower girl ) , Gaia Green , Recipe 420 Recharge mix , Maxibloom ( in water ) , or any good 4-4-4 general purpose.
Also .... Breeders lie - ACTUAL harvest time with autos are based on your own grow , your own environment/ skill . Those harvest times listed are from strain testing and from “ optimal “ conditions.
With autos they get done when they get done.